Printer&#39;s blanket and method of making



06. 4, 1934. T E I 1,983,352

PRINTER'S BLANKET AND METHOD OF MAKING I Filed May 16, 1930 PatentedDec. 4, 1934 PRINTERS BLANKET METHOD OF MAKING Theodore '1. Ellis,Worcester, Mass, assignor to New England Fibre Blanket Company,Worcester, Mass, a corporation of Massachusetts Application May 16,1930, Serial No. 452,960

32 Claims.

The present invention is concerned with methods of printing newspapers,and materials for facing the impression cylinders of rotary presses fornewspaper printing and analogous uses. It is further and moreparticularly concerned with woollen press blankets adapted to serve asthe facing or outer member of composite packings, for impressioncylinders of rotary printing presses. My purpose in making the presentapplication is to disclose and protect improvements which I have made inthe construction and mode ofrhanufacture of such blankets as the resultof long experience and exhaustive investigation and experiment, and togive to the art the benefit of the knowledge which I have gained throughmy experience and investigation. The following disclosure expresses theresults of continuous experience of nearly forty years as a pressmanemployed in newspaper ofiices, a. manufacturer and dealer in pressblankets and other supplies used in press rooms, and as an expertconsultant and adviser on problems and questions of practice arising inthe operation of newspaper printing presses. In the course of thisexperience during which I have become familiar with patents and otherpublications dealing with press blankets of various constructions, aswellas the articles actually used, I have been impressed with the dearthof exact knowledge of the basic funof the rotary printing press unit,and of the principles on which woollen blankets should be con structedto give them the characteristics needed to best meet the requirements ofthe printing unit. Therefore, before explaining the objects andcharacteristics of the present invention in detail, and

in order that these objects may be better under-- stood, I will describebriefly at this point the conditions existing in and among the membersof the printing unit.

The printing unit of a rotary press consists of a rotary type carryingcylinder and a rotary impression cylinder. In the standard'newspaperpress the type cylinder is called the plate cylinder and carries anumber of stereotype printing plates clamped to its outer surface.Ordinarily eight such plates are mounted on the same cylinder in twogroups, each group subtending approximately half the circumference ofthe cylinder and containing four plates arranged side by side lengthwiseof the cylinder. The impression cylinder is covered with a, facingfabric of a compressible and resilient nature in order'to compensate forirregularities in the stereotype plates. It is always customary tocouple two or more of such damentals that govern and control theoperation.

units together in a pair in order to print on opposite sides of thepaper sheet or web, and to provide a, number of pairs of units in thesame press for simultaneously printing thus a number of sheets. At thepresent day it is frequently necessary thus to couple as many as eightunits to print 64 pages at once in the same press, and

to run the press at speeds up to that which will produce 60,000newspapers per hour. Still larger papers, up to 96 pages, and fasterspeeds are now 65 advocated.

Each pair of printing units is supplied with a separate sheet of paper,which passes between the cylinders of one unit for printing on one side,called the first impression, and then between the cylinders of thesecond unit of the pair for printing on the opposite side, called thesecond impression. The speed of feeding the sheet through two units ofone pair must be the same in order to avoid either breaking the sheet byincreasing 76 tension on the one hand, or a progressive accumulation ofslack on the other hand, and all the sheets passing through the variouspairs'of units in the same press must be synchronized in order to bringthem to the assembling, cutting and fold- 80 ing instruments of thepress in theirproper sequence.

To synchronize 16 sheets, more or less, of brittle news print paper,each traveling at well over 30 feet per second, without a variation inspeed between the different sheets of as much as one ten-thousandth ofan inch per revolution is a serious problem. This problem is intensifiedby the fact that the surface of the'plate cylinder (constituted by thelines of type on the printy me Plates) is always uneven and ofchangeable unevenness, which requires the impression cylinder to becovered with a yielding facing, the surface of which tends to travel ata higher peripheral speed than the plate cylinder. The uneven surface ofthe printing cylinder adds a further complicating factor to the problem,and so also does the requirement that the compressible facing of theimpression cylinder must suffer as little deterioration as possible, butinstead must remain substantially the same while sus-' taining pressureapplication of great force by the printing plates with millions ofrepetitions.

These problems have long existed, and have been measurably solved by theblankets and pack- 1 5 ings manufactured under the patents of Frank E.Ellis, No. 1,296,782, March 11, 1919, and Cochran and Youngs, No.1,227,557, dated May 22, 1917; at least sufficiently to meet therequirements of the newspaper printing art up to witha' hithertoundreamed of number of pages at in the course of a run,

in the last few years. But recent developments in newspaper printinghave so intensified'the old problems, and introduced new ones, that thepre- Since the year 1925 there have been changes amounting virtually toa revolution in newspaper printing practice caused by the need ofprinting one time to take care of increased demands foradvertisingspace, and a demand for speeds of printing hitherto believedto be impossible. Prior to '1925, 32 pages was about the average size ofthe editions printed by the larger newspapers,

and this number of pages was the full capacity of an octuple pressgenerally operated at a maximum speed of 24.000 papers or less per hour.When the demand required'more than 32 pages at one printing, parts ofthe edition had to be printed on different presses and assembledtogether, which seriously slowed down the speed of production. Thiscondition led to the building of larger presses containing more printingunits; successively 40 page presses using 5 rolls of paper, 48 page 6roll, 56 page '7 roll, and 64 page 8 roll presses; and the operatingspeed was increased from 24,000 to 60,000 and more papers per hour. Achange was also made in the method of casting stereotype plates in orderto shorten the time needed for transferring the report of happenings tothe printed pages This change was the substitution of the so-called dryflong for the previously used wet flong as the matrix for forming typeoutlines in the face of the stereotype plates. The wet fiong was made upby hand in the newspaper office as needed. by pasting together three ormore sheets of soft matrix paper and two or more sheets of tissue paperon one face with a paste containing water; andv while wet was pressedagainst the hat dried-under a steam heated platen while in contact withthe form. The dry flong is a factory product supplied tothe newspaperprinters in a hard and dense, but water absorptive, state. For use it ishumidified by causing it to absorb about 20% of its weight of water,which makes it become semi-plastic while "remaining tough. It is thenmolded by being pressed against the type form, and immediately afterwardstripped from the form and dried in a machine called a scorcher, whereit is subjected. to the direct application of intense heat. The extremeheat causes the fiong to set and dry quickly, but it also warps theflong, and the resulting stereotype plates cast in the matrix providedthereby have an uneven surfacemuch exceeding the unevenness produced bythe wet fiong. However, the saving in time and other advantages due tothe dry flong make its use desirable. But the unevenness of the platesurface adds to the burden placed on the impression cylinder facing,

Limitations of time in newspaper press rooms, and the constant demand toget out the edition quickly, and the frequent changes of prohibit insuch press rooms the use of the hard packing with built up make-readiesused in the printing of books and magazines. In these classes ofprinting time is available for making truer printing plates, underlayinglow parts of the plates, and building up the impression cylinder packingto match irregularities in the printing plates, which is not availablein newspaper press rooms. Consequently in the latter the packing must bedeep or high type form. It was then inch of impression.

plates made enough to hold the paper up to low spots in the plate,compressible enough to yield for accommodation of high spots in theplate, and resilient.

enough to conform to the different irregularities of substituted plates.The changed conditions just described have imposed requirements whichthe previously used blankets cannot meet, and have presented a newproblem, the solution of a part of which constitutes the presentinvention.

In order to solve this problem it was necessary to learn all the factsand factors involved. A search of the literature of the art revealedthat there has never been any textbook written on newspaper printingpress operation, nor any public record made of the conditions existingand operating between the plate and impression cylinders of newspaperprinting presses, further than certain published writings of my own. Ihave also found by investigation that, first, the builders of newspaperprinting presses have had no exact knowledge of textiles and textilefibers, their densities, resistance to pressure, and resilience; and,second, that no manufacturers'of woolen and composition textiles haveexact knowledge of the requirements of newspaper printing presses ortheir method of operation or the requirements which the woollen blanketsmust meet. Consequently woollen blankets made for newspaper presses bydifferent manufacturers have varied greatly and different lots made inthe same mill have likewise varied; and

none has been able to perform satisfactorily the harder service requiredby the changed conditions of newspaper printing before mentioned.

In seeking a solution of these problems I have studied minutely theinteraction between plate and impression cylinders, determineddefinitely the requirements of the woollen impression facing, and, byinvestigation and invention, discovered the means for meeting thoserequirements. I will first state the conditions existing in the press,and then describe the new means constituting the present invention,which I have embodied in the structure of the facing material formeeting these conditions.

The pressure between plate and impression cylinders which obtains thebest printing results is approximately five pounds per inch of'length ofthe cylinders, for each one-thousandth of an Impression as used here isa technical term of the newpaper printing art and means the distance towhich the type faces of the printing plates extend within the normalcircumference of the impression cylinder facing. The standard thicknessof printing plates is seven sixteenths 'of an inch, but in practice thethickness is greater or less than standard by amounts up to three orfour thousandths of an inch, being usually above standard, and theextreme variatiori radially of the plate cylinder between high and lowparts of the plates amounts to' about-six thousandths of an inch. Aboutten thousandths of an inch of impression into the impression cylindersurface is required to compensate for plate variation and insure uniformprinting. To allow for this amount of impression, the surface of theblanket must, in its unstressed condition, be at least an equal distanceoutside of the pitch point of the impression cylinder; the pitch point 5between the plate 15;

and impression cylinders. These are, first, indentation of the typeprojections on the plate cylinder into the impression cylinder facing;second and third, a converging motion and then a diverging. motioncaused by the angular lines of the type faces as they approach andrecede from the zone of contact, in a circular path; and, fourth, acalender or rubbing motion of the surface of the impression cylinder dueto the fact that this surface is outside of the pitch point of theimpression cylinder. The fifth motion occurs when the cylinder bearingsare worn and some- -what loose, and is a vibrational movement whichtends to cause variations and imperfections in the printing. Thesemotions have a powerful tendency ,to disintegrate the blanket.Nevertheless the time limitations in newspaper press rooms, andconsiderations of cost forbid repacking the impression cylinders witheach change of printing plates, and demand that the same packing remainon the press during the printing of many millions of papers. Thecontinually repeated indentation of the type faces into the surface hasa disintegrating tendency, and the changing angularity of the type faceswhile indented into the impression facing tends to tear the surfacethereof. The impact load delivered by the plates under a normal pressureof about the order of thirty-six hundred pounds on the impressioncylinder, three hundred to five'hundred times a minute, is increasedmany times when, as not infrequently happens, the paper breaks and windsaround the cylinder before the press can be stopped.

The excess circumferential travel of the impression cylinder, whichunder best conditions is about one mile for each one million papersprinted, has a rubbing effect on the paper which also tends to destroythe impression surface.

This linear excess may be different in different units of the samepress, due to the surface on one impression cylinder being higher thanon an-- other, and this disparity tends to prevent perfectsynchronization of the paper webs passing through the different units.

The object of my invention then has been to produce a facing structureor material which will i a) Remain intact under unusual strains manytimes repeated during millions of impres- SlOIlS;

(b) Suffer no substantial elongation despite difference in radius andcircumferential speed from the plate cylinder surface;

(0) Be compressed and diminished in thickness normally not more than.001" with each million of newspapers printed;

(d) Absorb the multiplied pressure exerted when the paper breaks andWinds around the cylinder;

(6) Automatically compensate for uneven plate surfaces by yielding, andwithout being made permanently uneven in its thickness and on itssurface;

(I) Prevent surface disintegration due to angular strain;

(g) Prevent such movement within its structure as would cause chafingand cutting of its component fibers;

(h) Provide a predetermined density adequate to meet the differentprinting variables that exist;

(1') Provide adequate resisting pressure to the printing plate forclear, sharp printing, at a point about .006" below the surface;

(7') Provide a substantially frictionless outer surface permittingslippage in contact with the paper, without appreciable surface wear andwith the result of permitting perfect synchronization of the paper webwith other webs passing through units similarly equipped.

A further object is to devise methods of producing articles having thesecharacteristics; and to provide a method of adjustment of printing unitsand determination of the correct thickness of facing member for a givenimpression cylinder.

The foregoing objects have been accomplished by the new features of bodystructure and surfacing which are now described in connection with thedrawing. The end product of the invention is a printer's blanket ofwhich the body is constructed of wool fibers and the surface is composedof a flexible and elastic composition of nitrocellulose or equivalentcellulosic compound, with an emollient. Generically it is in the samecategory with the Ellis Patent No. 1,296,782 previously mentioned, butspecifically it differs widely therefrom and contains many features ofimprovement.

In the drawing,--

Fig. 1 is a section of one of the units of a rotary printing press toillustrate the character of machine with which my improved impressionfacing or blanket is used;

Fig. 2 is a fragmentary enlarged section of the impression cylinder ofsuch unit, showing the manner of securing the impression blanketsthereto in accordance with the present invention; I

Fig. 3 is a weavers diagram of'the preferred design and drawing-in draftfor the body structure of my improved blanket;

Fig. 4 is a plan view, on an enlarged scale of a fragment of the fabricwoven according to the diagram of Fig. 3;

Fig. 5 is a section of the fabric taken on line 5-5 of Fig. 4 parallelto the warp;

Fig. 6 is a sectional view of the blanket body after fulling andshearing;

Fig. 7 is a view similar to Fig. 6 showing the body structure afterpressing;

Fig. 8 is a similar section of the completed blanket with its cellulosiccoating on one face, this figure indicating also the successive steps inapplying such coating;

Fig. 9 is a fragmentary plan view of one end of the blanket as preparedfor application to the impression cylinder.

Like reference characters designate the same parts wherever they occurin all the figures.

Body structure.Novel features are provided herein respect of thequalityof wool used, the characteristics of warp and filling yarns, and theweave. Prime considerations in the finished structure are tensilestrength, uniformity, homogeneity, strong resistance to compression yetwith capacity for yielding considerably, and rapid resilience inreturning substantially to previous thickness after relief ofcompressing pressure. These qualities are obtained by the duality of thewoolused and the processes followed in spinning and weaving it. For thewarp, strength is particularly" important, since the blanket is appliedto the cylinder with. the warp running in the direction in which tensionis applied to tighten it; and for both warp and filling, andparticularly the filling, great capacity for felting and shrinking isrequired.

I have found that for the warp Delaine wool,

preferably that raised in Ohio, is superior to others, wherefore Ipreferably spin the warp from the grade of wool known as half blood Ohiostaple (60s). For the filling I prefer FallTexas fine clothing (64s to66s), for this grade of wool is characteristically elastic, sound, andpliable, and has exceedingly good felting qualities, being fine indiameter and short in length. Other wools substantially equivalent tothose named may be used however; as :half blood Michigan wool or amixture of the two for the warp, Australian instead of Texas for thefilling, etc. In fineness the grades above named are approximatelymidway between the coarsest and finest fibers. These wools areseparately sorted, scoured, and dried according to the usual standardpractice of woollen yarn manufacture. They are carded; and in carding adeparture from the regular routine is made. The weight of the roping ismade heavier than usual, being from '70 to 71 grains per 25 yards forthe warp, and '73 to '74 grains per 25 yards for the filling, as against60 to 62 grains respectively used 'in ordinary mill practice. Theheavier roping results in a more uniform and stronger yarn, withpronounced beardv on the surface, whereby more compact felting isobtained. 1

The carded wool roping is drawn and spun on mules or spinning frames.The warp yarns are given a tighter twist than the filling yarns (from 12to 13 turns per inch for the warp as against 9 to 10 turns per inch forthe filling) and is spun with the regular twist, while the filling yarnsare spun with the reverse twist. The use. of opposite twists in warp andfilling is important, and results in substantial uniformity in thicknessafter felting, eliminating the pronounced variation in cross sectionaldimension which occurs when the twist of both warp and filling yarns isthe same.

These yarns are woven into a plural-ply fabric united by binder warps.In the. specific construction illustrated in Figs. 3, 4 and 5, thefabric is two-ply and every fourth warp yarn is a binder which passesaround every fourth pick of the filling alternately in the two plies. aand a reprei to permit greater felting fabric to be built up in sent thebinder warps of opposite series, those of the series a passing over thepicks b, b of the face ply and around the picks c, c of the back ply,while the intermediate binders pass over the picks b, b of the face plyand around the picks c, c of the back ply. d, d and e, e represent theface warps of the two plies. i

The woven structure was designed as here shown with the object of makingan open fabric than is possible with a close weave, and to make thelength of warp yarns the minimum in proportion to the length of thefabric. The use of a relatively small number of binder warps passing ona long slant from one ply to the other, instead of weaving with the mainwarps passing from top to bottom of the fabric, prevents elongationunder stress. It will be understood of course that variations may bemade in the design of fabric from that here shown and described providedthe results last described are obtained in measurable degree. This openweave gives great felting possibility, enabling the thickness by thefulling process to a great excess over its thickness as it comes fromthe loom. Such great thickness gives bulk, from which any desired degreeof density in the finished product can be obtained by pressing. Animportant factor in this result is the tension of the binder warpsduring weaving.

They must be taut but not stretched appreciably. If these warps areslack, the surface of the goods after felting will show ridges; while ifsubstantially stretched during weaving theywill prevent proper felting.

FuZling.-The woven go ds are felted by a fulling process, in theperformance of which any of the suitable known fulling mills may beused. However, I have devised certain new steps by which superior andmore uniform results are obtained, which are here specified for thebenefit of the art. The mill rolls are driven at a relatively slowspeed, preferably at 125 revolutions per minute for 20" rolls, inorder'to avoid chafing the fabric and making it tender. The fulling soapis preferably applied cold; at any rate not heated more than necessaryand uniform application to the goods, and a soap mixture ofapproximately 7.5 ounces of dry flake tallow soap and .75 ounces of 58%pure alkali to the gallon of water is preferred. The temperature of themill is maintained within a range of approximately 65 F. to 90 F.,'andsoap .or water is added from time to time as needed to maintain a properlather or to prevent the soap from becoming pasty. There must be enoughsoap to prevent chafing, but not an excess. Excessive or pasty'soapslows down or stops the fulling process. The spring pressure on the millis equalized and a moderately heavy pressure is maintained. A

After starting the mill, the operation is carried on continuously, atleast without any extended stoppages or interruptions, until the fabrichas diminished by fulling as much as it will in'length and width. Whenno further fulling takes place this process is finished. In specificinstances of which observations have been made, the time required forcomplete fulling has been about eight hours, the reduction in length ofthe fabric in the neighborhood of from 35% to 40%, the reduction inwidth about 45% to 50%, and the increase in thickness 60% and more.

It is to be remembered that the foregoing specific values areillustrative of the nature a): the invention and not limiting as to itsscope. In fact considerable variations in thickness and density ofblanket material may be made in accordance with the principles of thisinvention tomeet particular conditions of different makes of printingpress, different individual presses, and the practices of differentpress rooms. These characteristics of the felted goods are affected bothby the thickness and the closeness of weave of the original fabric;which factors in turn are governed by the weight of the warp and fillingstrands, the number of plies in which the fabric is woven, and thedistance between-the warp strands and between the adjacent picks of thefilling. Blankets originally made of more than two plies are constructedessentially like the twoply design here shown.

The goods may be scoured after weaving and before fulling, butpreferably are not; for the fulling treatment itself thoroughly scoursand cleans the fibers. The fabric is not gigged or napped before ful ig, as the raising of a. nap does not increase the bulk of the feltedfabric nor improve its surface.

After fulling, the felted fabric is washed and r'insedin warm water, atapproximately 110 F. for a long enough time to remove all the soap. Thephenol-phthalein test is usedto determine freedom from soap. The goodsare then dried-on a tenter, with only sufficient to insure thoroughtension to hold them dried, it is sheared or cropped to remove the heavyfibrous surface and is thereafter sanded and again sheared. The firstshearing cuts off the heavy surface fibers. The sanding operation isperformed with a roll covered with sandpaper in Order to raise the endsof the fibers for the final shearing. A brush may be used instead of asand roll or together with'the sand roll. Preferably the felt is run anumber of times through the shear for shearing each face, and preferablythe ends are reversed between runs. In sanding a very light contact isused; just enough to raise-the ends of the fibers without cutting intothe body of the felt. The fibers are sheared very close to the body toproduce a velour character of finish with a short pile. 4

At this point, and thereafter at different stages in the commercialproduction of blankets, the fabric is gauged with micrometer calipers todetect imperfections and insure uniformity of the product. In gauging Iprefer to use an automatic dial micrometer, the spindle and anvil ofwhich are in diameter and the spindle is spring actuated toward theanvil to exert a pressure of 4 pounds per square inch. This statement ofpreference, however, is not a factor oflimitation, for other measuringdevices and other spring settings of this one may be used, provided careis taken to insure uniformity of pressure in taking all calipermeasurements. Records of these measurements are made and preserved forfuture reference.

Pressing-The goods at this stage are not firm, compact and dense enoughto meet the conditions previously outlined. They are brought to therequired density by a pressing operation, in the course of which theyare reduced in thickness to a gauge which has been determined by trialand test as the correct thickness for the purpose. But first, to insurethat the goods will retain the condition to which they are brought bypressing, they are impregnated with a sizing preparation which isadapted to act as a binder, to prevent springing apart of the fibersafter being released by the press, brought'to a prescribed condition ofdampness, and dried while under pressure.

The sizing preparation should be flexible and moisture resistant afterdrying, in order to insure substantial permanence in the condition to.

which the fabric is brought by pressing. The best composition for thispurpose known to me at present is a product obtained from the endospermof vegetable seeds. This product in the commercially refined conditionconsists of approximately 25% galactan and 64% mannan in combination,with small percentages of pentosans, albuminoids, cellular tissue andmineral matter. It is applied in a water mixture or emulsion containingpreferably about 2% of the endosperm product, reckoned on the basis ofthe evaporated dry concentration of this product. While I claim thesizing step of the combined process broadly without limitation to thespecific sizing material used, I also claim as a specific aspect of theinvention the use of this endosperm preparation in the step of pressingmy felt blanket structure to a prescribed thickness. The sizingpreparation is provided in a bath which is preferably maintained at atemperature in the neighborhood of 140 F. to 170 F. and the felt is runrepeatedly for the best results in rapid and thorough impregnation.

The correct moisture content at the time of pressing is obtained bydrying the fabric to substantially complete dryness after sizing, andthen dewing the fabric by passing it several times under a spray ofwater and rolling it up and letting it stand for a long enough time toeffect substantially uniform distribution of the moisture throughout thefabric. Standing for an hour and a half is usually enough for thispurpose, but the period may be lengthened or shortened at need. Theprocedure last described is preferred to that of pressing the goodswhile they are still wet or damp from the sizing step, because itaffords a better control of the moisture content at the time of pressingand enables exactly the right amount to be present. But the invention isnot limited thereto.

Pressing is performed in any way and by any means which will enter intosolution with the cellulose compound. and will accomplish the desiredresult, as between heated rolls, between a platen and a bed, or betweena roll or cylinder and a bed. A progressive and continthrough the bath,under pressure by rolls therein,

uous operation, as between rolls, or a roll and a curved bed, ispreferred. The best results are obtained by pressing in two stages;effecting about 75% of the desired reduction in thickness in the firststage, and the balance in the second stage. While a wide variation inthe finished thickness and density of the felt is obtainable by suitablepressure application, I find that the best results as to density,compressibility and resilience of the pressed felt are obtained if thereduction in thickness is about 20% from the thickness to which the feltis brought by shearing, before it has been sized, dried and dewed. Thepressure and heat application in the press are maintained for a longenough time to dry the felt substantially by the end of the secondpressing and to set the sizing agent and develop the moisture-resistingqualities of the latter. In other words, when a rotary press is used,the speed of traverse of the felt is regulated to the temperature of theroll and the thickness of the felt in such manner that the latter willbe relatively completely dry after the second run.

When thus pressed, the blanket is finished except for the application ofa'surface coating or layer, and has its final characteristics ofdensity, thickness, compressibility and resilience. In order that thesequalities may be provided in the desired-values and desired uniformity,the felt is gauged after pressing and the measurements compared withthose made after fulling. If any departure from standard is noted as toany of these characteristics the cause is ascertained at once andcorrection made.

. i Coating.-The blanket body thus constructed Details of -one specificcoattion so that its presence on the felt will be more 6 readilyapparent; but there is no oil or other emollient, and no opaque pigmentin the solution. Forall practical purposes then the first this solutionare made and quickly dried. The

total content of this solution constitutes the first coat, whetherapplied in one layer or more than one. The blanket with this coat iscalendered under heat, suitably after each application, to insure themaximum perfection of continuity in the coating material, whereby thismaterial is made to serve as a seal for the subsequently appliedcoatings to prevent the softening agent used in the later coatingspenetrating into the blanket body when affected by frictional heatgenerated under the conditions of use of the blanket.

Calendering at this time, and also after application of the subsequentcoats isan important step. Previous to each calendering the thickness ofthe goods is gauged, with the use preferably of the automatic dialmicrometer previously. mentioned, and the calender is set with its rollsabsolutely parallel and near enough together-to compress the goods.010", or thereabout, below the micrometer reading. Excessive or unevenpressure by the calender will distort the felt and cause subsequentcoatings of the nitrocellulose to flow unevenly. Hence great care istaken to insure exact evenness in each calendering operation. Afterbeing calendered the goodsare again gauged with a micrometer gauge todetect any unevenness which may have developed and inform the operatorif any correction is needed in the setting of the calender or thecomposition or mode of application of the coating solution. The firstcoating is indicated in the left-hand part of Fig. 8 of the drawing ase.

A second coating 6 is applied on the first coating, preferably in anumber of applications, and is calendered hot in the same way and withthe same care and precautions as the coating e'.'

This second coating is composed in part of nitrocellulose, but containsa large content of a softening agent or emollient in solution, andpigment. Preferably castor oil is used as the softening agent, sincethis is a non-drying oil and is well known to be mutually soluble withnitrocellulose and is otherwise suitable for the pur- The preferredproportions of ingredients 'inj'this solution are,--25% nitrocellulose,53%

castor oil, and 22% pigment, mixed with sufilcient volatile'solvent tomake it fluid or plastic enough to be spread over the fabric. Other oilswhich are sufficiently non-drying to serve my purpose may be used, andare substantially equivalent to castor oil within the scope of thisinvention. a

A third coating e of preferably. the same composition as the coating eor approximately the same, is spread over the latter and calendered hot,in the same manner as the coating e Finally a fourth or top coating e isapplied, likewise preferably in a number of successive applications.-This final coating is of a different composition than the precedingones, containing less emollient and pigment and more nitrocellulose. Itspreferred composition is 53% nitrocellulose, 34% castor oil and 13%pigment, with suflicient volatile solvent to make it plastic. It iscalenderedcold.

The composite coating thus constituted is built up to a substantialthickness, .012" more or less in the preferred forms of the invention.Its various compositions in different parts have an:

important effect. The large component of castor oil in its major partmodifies the harshness and brittleness of pure nitrocellulose, makingthe coating pliant and yielding when the blanket is secured to the presscylinder, and prevents the coating from parting or cracking, even thoughthe bottom layer thereof is substantially pure nitrocellulose. Suchbottom layer is so thin that it possesses the flexibility characteristicof thin films of even rigid substances, and it is besides unitedhomogeneously at all points to the superposed layers containing a largeproportion of castor oil. Thus it does not appreciably detract from theflexibility of the whole coating. Otherwise the bottom layer has animportant function, not merely in sealing in the oil content of the nextouter coating, but also in effecting a secure bond with the fibrousblanket body.

When applied it is in thin enough solution to surround and embed thesurface fibers of the body, but it is so limited in quantity and soquickly dried that it does not penetrate to any appreciable depth beyondthe outer fibers, and therefore does not stifiEen and harden the body,but leaves the latter with substantially the same elasticcompressibility and resilience as it possessed before being coated. Buttheinnercoating layer, by surrounding and solidifying on the surfacefibers of the body, creates such a firm bond that the entire tensilestrength of the outer fibers is available to retain the coating on thebody. a

The outermost layer of the coating is considerably harder than theintermediate layers because it contains a larger proportion ofnitrocellulose. The proportions between nitrocellulose and oil here aresuch as to make this layer flexible and at the same time tough andsemihard so that the type faces and their sharp edges.

do not make permanent indentations or cuts when pressed into it. Itscontent of nitrocellulose is sufilcient to prevent undue leakage orexudation of oil from the interior layers or oil reservoir, drawingtherefrom only sufficient oil to replace the loss due to frictionalheat. Its

outer surface is smooth, resistant to abrasion, and capable of slippingreadily on the surface of the paper. -Its flexibility, toughness andresistance to abrasion enable it to bear the repeated impact of printingplates and passage of the paper web without sensible deteriorationduring the printing of many millions of papers over periods of manyweeks. tion permits the slippage incident to its greater linear traveland enables paper webs passing over different impression cylinders inthe same press to be perfectly synchronized. In short, the compositionof said outer layer is practically ideal to serve the requirements ofthe outer blanket. I-Iowevenas the frictional heat generated in'theoperation 'of -the press causes the oil to be gradually drawn out to thesurface of thislayer and dissipated, said layer would eventually becomedry and brittle except forthe excess of oil content in theintermediatelayers. More oil is contained inthe latter than is neededfor flexibility alone of the intermediate part of the Its lowcoefficient of fric- 4 coating; the excess being provided as a reservesupply to replace losses of oil from the outer surface. Transfer of oilbetween parts of this composition takes place under the influence. ofheat, and when a deficiency of oil o'ccurs in the outer layer, a demandfor oil to supply the loss is caused, which draws sufficient oil fromthe intermediate layers to satisfy it. Thereby the outer surface ismaintained in proper, condition substantially as long as the blanketremains serviceable otherwise.

In thus describing the total coating-as consisting of four definitelayers, I have not intended to state narrow limitations as to the numberand compositions of the intermediate layers. Each of the layers,so-called, of the foregoing description consists preferably of severalsubsidiary applications or coatings, and these latter may vary from oneanother more or less as to their content of nitrocellulose and oil.Thus, for instance, after the first coat or application, which containsno oil, has been applied, the following coats may contain first a littleoil, and then relatively more and more oil until the coating has beenbuilt up to the region of greatest richness in oil, after which the oilcontent of successive applications may be progressively diminished untilthe outermost coating of substantially the composition best suitedforthe outer surface has been applied. That is, thegeneric invention withregard to the coating, of a variation in its composition betweeninnermost and outermost layers, with the correct amount of oil in theoutermost layer, an excess'of oil in the middle layers, and no oil orvirtually none in the innermost layer, may be obtained in various ways,all within the scope of protection which I claim.

The sanding and close shearing of the blanket body, previouslydescribed, severs the surface fibers and leaves a multitude of free endswhich stand up more or less and are in better condition to be surroundedand embedded by the coating material than would be the case if they werenot thus out. They eifect a much firmer attachment of the facing thancan be made with an unsheared felt. Such surface fibers project throughthe innermost layer of the coating and to some extent into the second,and possibly the third, layer, but they all terminate well within theouter surface of the coating.

The innumerable fibers projecting above the main structure of the feltalso provide a thin intermediate cushion between the body structure andthe facing coat. This intermediate cushion is a leveling factor forabsorbing plate variation, and it takes up the greater part of thesevariations without transmitting much compression to the body of thefelt. But the compressibility and resilience of the entire body isavailable in reserve for accommodating excessive inequalities in theplate surface.

These factors of the composite blanket cooperate topreventdisintegration' and permanent compression, at least to anyobjectionable extent. Tests of material constructed as herein describedhave shown no more than .010" decrease in thickness after printingtwelve million newspapers, the surface coating being then still intactand the surface fibers of the body erect.

Tests of the blanket material for compression and recovery or comebackshow 98% recovery to original thickness (which is practically completerecovery) five minutes after release of pressure which has compressedthe blanket 10% from its manufactured thickness. This quality ofresilience is greater than necessary to meet ordinary printingconditions and enables the blanket to recover from the impression of oneplate or set of plates and absorb the impressions of different plates.

Felt blankets may be used singly and alone on iron impression cylinders,or in conjunction with other blankets of the same or different construction. A desirable combination is to place one over an under blanketcomposed largely of cork, the latter having additional compressibilityand cident occurs such as the breaking of the paper web and wrappingofthe paper several times around the impression cylinder before thepress blanket.

Attachment of blanket to impression cylinder.-Impression cylinders ofnewspaper printing machines are made smaller in diameter than the pitchdiameter. This is necessary to provide space for the resilient blanketor packing. Printing press manufacturers have their own individual.

standards. Some cut the cylinder surface only .125" below the pitchline, others .156" below, and others more or less than the above namedvalues. To meet these conditions my blankets are manufactured in variousthicknesses or gauges, but all according to the principles hereinbeforedescribed and following substantially the same steps.

The standard impression cylinders are provided with a longitudinal slotat one side from its outer surface into an interior cavity. In thiscavity are mounted one or more reels to which one end of the blanket issecured and by rotation of which it is put under tension. .The practiceheretofore has been to secure pins within one edge of the slot, suchpins being about in diameter and spaced about 2" apart, and to impaleone end of the blanket on these pins while the other end is secured toone of the reels after wrapping the blanket around the cylinder. Thismethod of attachment' is unsuitable to secure blankets under the tensionrequired to meet the changed conditions of modern printing. My blankethas a tensile strength of 9,000 pounds in a width of 36", which is thewidth generally used. But pins of the type and arrangement heretoforeused provide means of carrying a stress of only about 280 pounds, andtensions greater than this will cause the blanket to tear away from thepins. Toovercome this condition I sew a heavy strip of canvas, shown atf in Fig. Q "0 each end of the blanket, and secure both Q ps to thereelsg, tightening the blanket by reel in both ends. By this meanssubstantially the tensile strength of thebianket is made availa. i eded.

Zn thus particularly describing the principles and details ofconstruction. of my new felt press blanket, I have intended to give allparticu- .ais necessary for enabling those skilled i he art to practicethe invention. These particul contain the best means, so far as nowknown to me, for meeting and, satisfying the exacting requirements ofthe modern newspaper printing presses. At the same time I desire it tobe understood that-I claim protection for all variations from the exactparticulars herein set forth which come within the scope of novelty ofthe new steps contained therein. It is to be understood furthermore thatI do not limit my protection in all its phases to the combination of ablanket body with .a facing coat of nitrocellulose or its equivalent,

but claim independently the novel characteristics of the blanket bodyalone. Such body is not inoperative in the absence of the attachedfacing 'resiliency to absorb excess pressure when an acars fulled tofelted condition to a definite thickness substantially greater than itswoven thickness.

2. A felt printers blanket consisting of felted loosely woven superposedplies made of woollen warp and filling yarns, some of the warps beingbinders passing about picks of the filling, first in one ply and then inthe adjacent ply, the felt being held under resilient compression bybinder material therein, which is flexible, moisture resistant andsubstantially permanent after drying.

3. A printers blanket comprising a fabric loosely woven from woollenyarns, said fabric being fulled and felted and held permanentlycompressed by a binder material which is flexible and moistureresistant; but havingcapacity for further compression and rebound inuse.

4. A woven woollen printers blanket held in a state of permanentcompression by a binder material containing galactan, said bindermaterial being flexible and moisture resistant.

5. A woven woollen printers blanket held in a state of permanentcompression by a binder material containing mannan, said binder materialbeing flexible and moisture resistant.

6. A woollen felt blanket for use on the im-' pression cylinder of anewspaper printing press, comprising the product of 'a loosely wovenconstruction of loosely twisted woollen yarns after being fulled tosubstantially increased thickness and compressed to a thicknessintermediate the woven and fulled thicknesses, and containing bindingmaterial which is flexible, moisture resistant .and substantiallypermanent after drying and -maintains the blanket-in its compressedcondition with capacity for further compression and elastic reboundtherefrom.

ric loosely woven from'high felting woollen yarns,

'7'. A printers blanket made of a woven woollen fabric, fulled, feltedand held in resilient corn.-

-pressionby a quantity of size substantially equal to that remainingafter the felt has been saturated in water containing in the order of 2%of galactan-mannan size and dried.

8. A felt printers blanket made of a woven, woollen fabric fulled,felted and held in resilient.

compression by galactan and. mannan binder 'material.

9. A felt printers blanket made of awoven woollen fabric, fulled, feltedand held in resilient compression by vegetable seed gelactan-mannanbinder material.

10. A printers blanket comprising a felted fabsaid fabric being highlyfelted, the felt being held compressed in a state of high density andresilience by. a binder material which is flexible, mois- 1 tureresistant and substantially permanent in dry condition.

11. A coated printers blanket comprising a woven, fulled and compressedblanket body composed of wool fibers, in whichthe fibers are held in anormal state of compression by binder material; and a composite coatingof wear-resisting flexible cellulosic matter in intimate union with thesurface fibers on one side of said body,

said coating containing an oily s'oftener'except in its innermost orbottom zone which is substantially oil free.

12. A printers blanket comprising a compressed felted body of woollenfibers containing dried galactan-mannan binder material which isflexible, moisture resistant and substantially permanent, bindingtogether the compressed fibers in a condition permitting further.compression and rebound therefrom: and a substantially solid surfacecoating of flexible wear-resistant and ink-repellent matter bonded tothe outer fibers of said body.

13. A printers blanket comprising a woollen felt body and a coating ofwear-resisting, flexible cellulosic substance in a plurality of layershaving respectively different compositions; the innermost of saidcellulosic layers surrounding and embedding the surface fibers of thefelt body and being of a solid composition which firmly grips suchfibers, the intermediate layer being a mixture of the cellulosicsubstance with an oily softening agent, and the outermost layer beingalso a mixture of the cellulosic substance with the softening agent buthaving a substan- 1 felt body and a coating comprising in its inner- 1most part hard and elastic substance surrounding and gripping thesurface fibers of the body, its outermost partbeing composed of thesubstance mixed with a sufficient content of oily softening agent torender it flexible while still being tough 1 and firm, and itsintermediate portion being a mixture of the substance and oily softeningagent, but containing a larger relative content of the softening agentthan the outermost: portion serving in effect as a reservoir containinga surplus supply of the softening agent to replenish losses of thesoftening agent from the outer surface of the coating.

15. A printers blanket comprising a woollen felt body having exposedfibers on its surface and j a coating comprising a cellulose compoundwith an admixture of oily softening agent applied to the surface of thesaid felt body, the innermost portion of said coating being composed ofcellulose compound substantially free of said oil? 1 softening agent andsurrounding and gripping the outermost fibers of said body.

16. A printers blanket comprising a woollen felt blanket body and acoating on'one surface thereof comprising an inner layer ofsubstantially oil-free nitrooellulosesurrounding and grippingthe'surface fibers of the body, an intermediate layer bonded to theinner layer containing nitrocellulose and a relatively largev amount ofoily softening agent, and an outer layer bonded to the intermediatelayer containing a greater proportion of nitrocellulose and a lessproportion of the oily softening agent than the intermediate layer.

1'1. The method of making a highly'dense and resilient printers blanketwhich comprises loosely weaving high felting woollen yarns, fulling saidfabric thoroughly to produce substantially maxiing it with heat whilecompressed in a highly dense and resilient state.

18. The method of making a highly dense and ness, sizing the so feltedmaterial, compressing resilient printers blanket which comprises looselyweaving a plurality of plies of woollen fillingyarns, with woollen warpyarns 'to produce a loosely woven thick fabric, fulling said fabricthoroughly to produce substantially maximum feltedthickness,'impregnating the felt with vegetable seed galactan-mann'ansize, strongly compressing the sized felt while damp and drying it whileunder such compression with heat whereby a dense resilient substantiallymoisture-proof printers blanket is obtained.

19. The method of making a felt printers blanket which consists ininterweaving woollen warp yarns, having a twist in one direction, withwoollenfilling yarns, having a twist in the opposite direction, into aloose fabric, fulling saidfabric, and compressing the fabric, theopposite twists in the warp and filling yarns giving substantialuniformity of thickness after fulling.

20. The method of making a felt printers blanket which consists ininterweaving woollen warp yarns having a twist in one direction, withwoollen filling yarns, having a twist in the opposite direction, into aloose fabric, fulling said fabric, the opposite twists in the warp andfilling yarnsgiving substantial uniformity of thickness after fulling,sizing the fabric with a binder material which is -flexible, moistureresistant and. substantially permanent after the application of heat andpressure, and compressing the fabric with heat, whereby the blanket isheld in its compressed condition with capacity when in use for furthercompression and elastic rebound.

21. In a method of making woollen felt printers blankets, the stepswhich include spinning yarns with-a loose twist and interweaving suchyarns with a loose weave to form a fabric designed to be substantiallyand definitely increased in thickness by fulling, fulling said fabricfor a suificient length of time and with such control of the fullingoperation as to accomplish a substantial and definite increase inthickness of said fabric, sizing the fabric with a binder r'fiaterialwhich is flexible and substantially permanent after drying, andcompressing said sized fabric 'under heat and, pressure to a definitethickness.

22. The method of producing a printers blanket which consists in cardingwool of medium fineness to make roping of a weight in the order vof 70to '75 grains per each 25 yards of length,

spinning such roping into yarns with a loose twist, interweaving suchyarns loosely as a fabric with a pluralityjof plies of filling yarns andinterlocked warp yarns, fulling the fabric to closes;

ly felted condition and greatly increased thickthe sized felt .in dampcondition, and under pressure; I

23. The method of making a woollen felt printers blanket which comprisesfulling a loosely woven woollen structure to, substantially increasedthickness and felted condition, distributing through the feltedstructure in a liquid vehicle a. galactan-mannan sizing material whichis moisture resistant and has substantially permanent binding propertieswhen dry, compressing the sized felt while damp to less than its fullcapacity for compression, and drying the felt'while under pressure, toproduce a woollen body with its fibers held by said sizing material inanormal state of compression and having capacity for further compressionand resilient rebound 24. In the production of a felted and compressedwoollen printers blanket, the method of maintaining a substantiallyconstant state of comdrying it pression in such blanket, which consistsin impregnating the felted blanket body, before compression, with sizingwhich is flexible, moistureresistant and substantially permanent afterdrying, compressing the sized felted body while damp and simultaneouslydrying it by heat.'

25. The method of giving a. predetermined and substantiallypermanent'density to a felt printers blanket which consists inimpregnating the uncompressed blanket with water containing in the orderof 2% of a dried concentrated galactanmannan sizing, compressing thesized blanket while damp and at the same time drying it under pressurewith heat.

26. The method of giving a predetermined and 90 substantially permanentdensity to a felt printers blanket, which consists in impregnating theuncompressed blanket with water containing sizing material which isflexible, moisture-resistant and substantially permanent after drying,drying the blanket, then moistening it. with water to a predeterminedcondition of dampness, compressing the damp blanket and simultaneouslydrying it with heat application.

2'7. The method of compressing a felt printers blanket to apredetermined and substantially constant condition of density, whichconsists in distributing throughout'the structure of the blanket abinder consisting essentially of vegetable seed galactan-ma'nnan sizing,drying the blanket, then moistening it with'water to a predeterminedcondition of dampness, compressing thedamp blanket and simultaneouslydrying it'with heat application.

28. The method of manufacturing a compressed 110 woollen felt printersblanket with maintenance of given conditions of compression and density,which consists in fulling a loosely woven body composed of woollenyarns, with control of the fulling operation to bring the material to apredetermined thickness, sizing thefulled goods with. amoisture-resistant sizing material, and pressing the sized goods to apredetermined percentage of its original fulled thickness, withadjustment of the compressing pressure and proce- 120 dure to maintainthe prescribed thickness.

29. The method of manufacturing compressed woollen felt printers blanketwith maintenance of fixed conditions of thickness, density, andcompressibility, which consists in interweaving loosely twisted warp andfilling yarns into a loosely woven body, fulling the woven body withcontrol and adjustment of the fulling step to produce a felted body ofsubstantially greater thickness than the woven structure, sizing thefelted 13w body with a moisture-resistant. sizing material, compressingthe felt to a predetermined thickness,

' and setting the sizing material by heat while the felt is underpressure.

30. The method of making compressed woollen 13 5- felt printersblanketswith maintenance of given conditions of thickness, density andresilience, which consists in interweaving woollen warp and fillingyarns of given weights into a structure having a given thicknessand'spacing of component yarns, fulling such body to a felted conditionand substantially increased thickness with control and adjustment of thefulling step to maintain such compound dissolved in a volatile solventand substantially free from oil and evaporating the solvent so quicklythat the cellulose compound surrounds the fibers of the blanket whichare at and ,near the surface thereof, only, and hardens with a firm gripand bond upon such fibers; applying a further coat of the cellulosecompound mixed with a large proportion of emollient oil, and a to thesurface of the felt and calendering such surface with heat, so that thecellulose compound is quickly dried and set in embedding and grippingengagement with the outer fibers of the felt, and

is prevented from penetrating substantially into the interior of thefelt; then spreading on the first-named coating an intermediate coatingof a solution of cellulose compound in a volatile solvent mixed with anexcess of emollient oil; calendering the said intermediate layer withheat; and finally spreading an outer'layer of cellulose compound in avolatile solvent containing a smaller proportion of emollient oil, thecontent of oil in the last-named layer being sufllcient to prevent thecellulosic content thereof from becoming brittle when freed of solvent,but small enoughv to permit it to be tough and solid when dried, andcold-calendering the last named layer.

s THEODORE T. ELLIS.

